Magnetic switching apparatus

ABSTRACT

A switching apparatus comprised of a base with a magnet and a block made of magnetic material coupled to the magnet while contacting a magnetic pole surface of the magnet, a spring plate which is magnetically coupled to the base and which is extended between both ends of the base, a short-circuiting portion made of magnetic material which is located at a position opposite to and near the magnetic pole of the magnet of the block made of magnetic material of the base while the short-circuiting portion remains away from the base whenever the spring plate is at the home position, and at least one galvano-magnetro effect device which is located at a position on the said magnetic block of the base so that the quantity of magnetic flux to which the galvanomagnetro effect device is exposed varies when the shortcircuiting portion contacts the base.

United States Patent Masuda et a].

[54] MAGNETIC SWITCHING APPARATUS [72] Inventors: Noboru Masuda,Kawaguchi; Tunekazu Kobayashi, Kawasaki, both of Japan Assignee: DenkiOnkyo Co. Ltd., Tokyo, Japan Filed: Oct. 14, 1970 Appl.No.: 80,601

Oct. 16, 1969 Oct. 16, 1969 Oct 25, 1969 Japan... ....44/98424 Japan.......44/98425 Japan ..44/l0l030 US. Cl. ..338/32 H, 323/94 H ..H0lc 7/16Field of Search ..338/52; 324/45, 46; 323/94 H;

[56] References Cited UNITED STATES PATENTS 3,537,046 10/1970 Hubrich etal. ..323/94 H X [451 July 11, 1972 [57] ABSTRACT A switching apparatuscomprised of a base with a magnet and a block made of magnetic materialcoupled to the magnet while contacting a magnetic pole surface of themagnet, a spring plate which is magnetically coupled to the base andwhich is extended between both ends of the base, a short-circuitingportion made of magnetic material which is located at a positionopposite to and near the magnetic pole of the magnet of the block madeof magnetic material of the base while the short-circuiting portionremains away from the base whenever the spring plate is at the homeposition, and at least one galvano-magnetro effect device which islocated at a position on the said magnetic block of the base so that thequantity of magnetic flux to which the galvano-magnetro effect device isexposed varies when the short-circuiting portion contacts the base.

10 Claims, 10 Drawing Figures Patented July 11, 1972 3,676,828

3 Sheets-Sheet 2 F/G. 5 3O 20 Patented July 11, 1972 3 Sheets-Sheet 5WG/O 3 r N a 2/ a 3 4 o /w I w disadvantages.

MAGNETIC SWITCHING APPARATUS BACKGROUNDOF THE INVENTION Conventionalswitching apparatus generally exhibit such disadvantages as poor contactdue to wear of the contact point resulting from frequent sliding;therefore, it has been demanded in recent years that acontactlessswitching apparatus be produced using the galvano-magnetro effectdevice. Since this type of switching apparatus is designed so that themoving yoke is arranged to form one side of the magnetic path and a gapin the magnetic pathand the width of this gap is changed in accordancewith movement of a moving yoke to vary the quantity of the magnetic fluxwhich is applied to the galvanomagnetro effect device, the contactlessswitching apparatus is defective because the magnetic force of themagnet which forms the magnetic path reduces due to repeated variationof reluctance and the gap width cannot be greatly varied because theswitching apparatus is compact and, accordingly, it is difficult togreatly vary the magnetic flux to be applied onto the galvano-magnetroeffect devices.

The present invention is intended to provide a switching apparatus withsimple and inexpensive construction using galvano-magnetro effectdevices, devised to eliminate the said SUMMARY The present inventionprovides a switching apparatus comprised of a base made of magneticmaterial which is composed of a magnet and magnetic block coupledcontacting the magnetic pole surface of the magnet, a spring plate madeof magnetic material which is magnetically coupled to the base and isextended between both ends of the base to form a closed magnetic pathwhich connects magnetically both ends of the base and the center portionof the'spring plate which is located opposite to the base, a depressingmeans which depresses the center portion of the spring plate to bendtoward the base, a short-circuiting portion made of magnetic materialwhich is provided at a position on the internal surface of the springplate which is opposite to a portion of the magnetic block near themagnetic pole of the magnet and which forms a closed short-circuitingmagnetic path which shorts both magnetic poles of the magnet when thespring plate is bent to contact or approach the base, at least onegalvano-magnetro effect device such as, for example, a Hall effectdevice and a magnetro-resistance device, which is arranged at the baseso that the quantity of magnetic flux is varied when the closedshortcircuiting magnetic path is formed between the both magnetic polesof the magnet by the short-circuiting portion, and an external inputpower supply and external load connected to the galvano-magnetro effectdevice.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is illustratedin detail in the accompanying drawings whereof:-

FIG. 1 is a front view of the switching apparatus of an embodiment ofthe present invention;

FIG. 2 is a front view of the actuated state of the switching apparatusshown in FIG. 1;

FIGS. 3 to 6 are the front views of the switching apparatus of otherembodiments of the present invention;

FIG. 7 is a plan view of the switching apparatus shown in FIG. 6;

FIG. 8 is a front view of the switching apparatus of another embodimentof the present invention;

FIG. 9 is a isometric view illustrating part of the switching apparatusshown in FIG. 8; and,

FIG. 10 is a plan view of the switching apparatus of another embodimentof the present invention.

DETAILED DESCRIPTION an apparatus comprised of a base 10 composed ofmagnet 11,

magnetic block 12 which is coupled to the magnet, contacting one pole,such as N magnetic pole of the magnet, yoke 13 which is fixed to the Smagnetic pole of said magnet 11 and projects upward and yoke 13 which isfixed to the free end of said magnetic block 12 and projects upward at aposition opposite to yoke 13.

Straight elastic spring plate 20 made of magnetic material is mounted onthe free ends of said yokes 13 and 13' so that both ends of the springplate can be slid.

Both ends 21 and 21' of said spring plate 20 are formed in the reversedU-shape and are mounted on the free ends of yokes l3 and 13' so thatboth ends of the spring plate do not come ofi the yokes even when thespring plate is depressed and bent.

Short-circuiting portion 30 made of magnetic material is provided at theinternal surface of spring plate 20 which is adjacent to the base 10 sothat portion 30 can approach or contact a portion near the end of saidmagnetic block 12 which contacts the magnet when the spring plate isbent.

Galvano-magnetro effect devices 40 and 40' are respectively provided ata portion which comes in contact with said short-circuit portion 30 anda surface which contacts yoke 13', of said magnetic block 12 and areconnected to the same or different power supplies and load circuitswhich are not shown.

The switching apparatus according to the present invention is devised asmentioned above. Spring plate 20 by virtue of its spring memory,stretches between yokes 13 and 13' as shown in FIG. 1, when the springplate is released and returned to the home position. When spring plate20 is depressed towards the base by a depressing means M spring plate 20is bent and shortcircuiting portion 30 contacts galvano-magnetro effectdevice 40 on the base. Accordingly, in this embodiment of the presentinvention, a closed circuit in which magnetic block 12 and magnet 11 areconnected in series is formed when no pressure is applied to the springplate whereby the magnetic flux is concentrated onto galvano-magnetroeffect device 40' at the yoke side and the closed short-circuitingmagnetic path, which shorts both ends of magnet 11, is formed whenspring plate 20 is bent. Thus the magnetic flux concentrates ongalvano-magnetro effect device 40 on the base.

In this embodiment, therefore, it is possible to alternately concentratethe magnetic flux onto one of the two galvanomagnetro effect devices 40and 40' by depressing or releasing spring plate 20, and to therebyactuate the galvano-magnetro effect devices.

In said embodiment, the short-circuiting portion can be arranged tocontact galvano-magnetro effect device 40 or to approach it. Whenarranging the short-circuiting portion to contact the gaIvano-magnetroeffect device, it is desirable to coat the external surface ofgalvano-magnetro effect device 40 with a protective cover.

The switching apparatus according to the present invention can also beconstructed as illustrated in FIGS. 3 to 5.

FIG. 3 illustrates a switching apparatus which is provided with magneticblocks 12 and 12 respectively connected to both ends of magnet 11 andcorrugated flexible springs 22 and 22 which causes the short-circuitingportion to contact and separate from the upper surface of the base. Withthis embodiment, the spring plate can operate lightly.

FIG. 4 illustrates a switching apparatus which is provided with a springplate the both ends 23 and 23' of which are bent to be oppositelyarranged at their free ends and are fixed directly to both ends of base10.

The switching apparatus of the said embodiment is advantageous in thepoint that its construction can be simplified because it is notnecessary to provide a yoke at the said base.

FIG. 5 illustrates the switching apparatus in which base 10 is U-shaped,spring plate 20 is extended between free ends of the said base andgalvano-magnetro effect device 40' is fitted into slit 12a provided atmagnetic block 12.

With this embodiment, the switching apparatus is advantageous in thepoint that length L of base 10 can be reduced.

As shown in the above embodiments, the galvano-magnetro effect devicesof the switching apparatus according to the present invention can beplural in number as FIG. 1 or single as shown in FIGS. 3 to 5. Whengalvano-magnetro efiect device 40 is inserted between yoke 13 andmagnetic block 12 only, as shown in FIG. 3, the density of the magneticflux to galvano-magnetro effect device 40' is forced to suddenlydecrease by contacting short-circuiting portion to said base 10 and isthus inhibited to operate.

When galvano-magnetro effect device 40 is mounted on the base only, asshown in the FIG. 4, the magnetic flux is concentrated ontogalvano-magnetro effect device 40 by contacting the short-circuitingportion to base I and said device 40 can be actuated; whengalvano-magnetro effect device 40" is inserted into the barrel portionof magnetic block 12, as shown in FIG. 5, galvano-magnetro effect device40 can be actuated as in the case of the switching apparatus illustratedin FIG. 3.

FIGS. 6 and 7 illustrate a switching apparatus in which both ends ofsaid spring plate 20 are made up as coiled portions 24 and 24' so thatthe spring plate can be bent by virtue of coiled portions 24 and 24.

In this embodiment, said base is made straight, on both ends of whichcoiled portions 24 and 24 of spring plate are mounted.

Said base 10 is housed in base frame 50, made of non-magnetic material,which is open upward. Support frames 51 and 51, which project above theupper surface of base 10, are provided at both ends of said base frame50.

Said support frames 51 and 51 are provided with long holes 52 and 52through which shafts 53 and 53 fixing coiled portions 24 and 24 of thespring plate at their centers are mounted so that the shaft can belowered.

In the switching apparatus shown in this embodiment, coiled portions 24and 24 expand between the shafts and the base when spring plate 20 isreleased and pressure-contact base 10 while pressing said shafts 53 and53 onto the upper ends of long holes 52 and 52' as illustrated in FIG. 6to keep magnetic connection. When spring plate 20 is depressed and bentas shown with broken lines, coiled portions 24 and 24 are constricted anamount equal to the bend of spring plate 20 at its center and arepressed onto base 10 by a force applied to spring plate 20 whilelowering shafts 53 and 53' in long holes 52 and 52 thus maintainingmagnetic connection.

As clearly known from the above description, this embodiment of thepresent invention provides a switching apparatus in which constrictionand expansion of coiled portions 24 formed at both ends of spring plate20 bends or stretches the spring plate. Accordingly, a coiled portioncan be formed at only one end of said spring plate 20 or, to maintainmagnetic connection of coiled portion 24 and base 10, shaft 53 tosupport the coiled portion can be made of magnetic material and can beattached to a support frame made of magnetic material such as, forexample, the yoke which is fixed at base 10.

In this embodiment, spring plate 20 is reset by coiled portion 24 and,therefore, the ability is that restoration of the spring plate can belarge. For this reason, further ability is that a spring plate bendingmeans which is not shown can be simultaneously restored along withrestoration of the spring plate and base 10 can be secured in base frame50 with a pressing force taking shaft 53 and 53' of coiled portions 24and 24 as the fulcrum if the switching apparatus is constructed asillustrated in FIG. 6.

FIGS. 8 through 10 illustrate a switching apparatus in which rollers 60and 60' made of magnetic material are arranged opposite to both ends ofbase I0 which is formed straight, making it possible to bend springplate 20.

Said rollers 60 and 60' are mounted at both ends of base 10 so that theycan roll toward each other and are provided with resetting springs 61and 61', which hold the rollers at a given position at all times.

Both ends of spring plate 20 are fixed to the outer surfaces of saidrollers 60 and 60 so that the spring plate is magnetically coupled tobase 10; accordingly, rollers 60 and 60 are rotated'in a direction toapproach each other as shown with broken lines when spring plate 20 isbent and are rotated by resetting means 61 and 61' apart from each otherwhen spring plate 20 is released.

A spring is not always necessary for resetting the' rollers and thespring plate (or the repercussion of the spring plate) can be used asthe resetting means for the rollers by curling the ends of the springplate along the surface of each roller.

As clearly known from the above description, this embodiment makesroller 60 possible to bend the spring plate as well as to maintainmagnetic connection of spring plate 20 with base 10; accordingly, aroller can be attached to one end only of spring plate 20 as illustratedin FIG. 10. It is desirable to provide guides 62 and 62 to ensuremovement of the rollers as shown in FIG. 9.

This embodiment is intended to rotate rollers 60 and 60 when springplate 20 is bent. A reluctance increasing part 60'a is provided. Means60a can, for example, be a non-magnetic insulating layer of an elongatedgroove positioned along the axial direction of roller 60' mounted on theend of magnetic block 12. The groove 60a contacts base 10 when springplate 20 is bent as shown in dotted lines in FIG. 8. This ensures thatthe density of the magnetic flux applied to galvano-magnetro effectdevice 40 can be large when short-circuiting portion 30 forms the closedshort-circuiting magnetic path.

With the same reason as above, the reluctance increasing part can beprovided at the base side. In this case, it is satisfactory to providean insulating layer on the base where roller 60 comes when spring plate60 is bent toward the upper surface of the magnetic block of the base.

When constructed as mentioned above, the switching apparatus accordingto this embodiment makes it possible for the density of the magneticflux applied to galvano-magnetro effect device 40' to be greatly reducedbecause roller 60' separates from galvano-magnetro effect device 40 whenthe spring plate is bent if a galvano-magnetro effect device is arrangedbetween roller 60 at the magnetic block side and magnetic block 12.

The switching apparatus according to the present invention is devised asillustrated with said embodiments; therefore use of this switchingapparatus results in the following advantages.

The switching apparatus can be mass-produced at low cost because of itssimple construction and the galvano-magnetro effect device permitsdesigning of the entire apparatus in a compact size.

The demagnetization of the magnet can be inhibited because a closedmagnetic path including the magnetic block is formed when the springplate is stretched and the closed short-circuiting magnetic pathincluding the short-circuiting portion is formed when the spring plateis bent.

The density of the magnetic flux applied to the galvanomagnetro effectdevice being suddenly changed with contact and separation of theshort-circuiting portion from the base ensures accurate motion of thegalvano-magnetro effect device.

In the case of switching apparatus in which the short-circuiting portioncontacts the base, the short-circuiting portion comes in contact withthe base without friction and therefore wear is extremely small and,even though it wears, poor contact will not be caused because theshort-circuiting portion can be pressed onto the base.

What is claimed is:

l. A switching apparatus comprised of a. a base made of magneticmaterial which is composed of a magnet and a magnetic block coupled toand contacting a magnetic pole surface of the magnet, said base havingends;

b. a spring plate made of magnetic material which is extended betweenthe ends of the base while being coupled magnetically to the base andarranged so that it is positioned opposite to the base;

c. means to bend the spring plate toward the base;

d. a short-circuiting portion which is arranged between the spring plateand the base so that it can approach the base to form a closedshort-circuiting magnetic path including the magnet when the springplate is bent toward the base; and

e. at least one galvano-magnetro effect device which is provided on thebase so that the density of the magnetic flux applied to the devicevaries when a closed short-circuiting magnetic path is formed with theshort-circuiting portion by bending of the spring plate.

2. A switching apparatus, according to claim 1, wherein at least onegalvano-magnetro effect device is provided at the magnetic block of thebase so that the short-circuiting portion can contact or approach thebase when the spring plate is bent.

3. A switching apparatus, according to claim 1, wherein yokes areprovided at both ends of the base so that these yokes project parallelto each other above the base and the ends of the spring plate areslidably attached to the yokes.

4. A switching apparatus, according to claim 1, wherein the ends of thespring plate are curved to form free ends opposite to each other andthese free ends are fixed to the ends of the base.

5. A switching apparatus, according to claim 1, wherein at least one endof the spring plate is coiled and the portions thus coiled aremagnetically connected to the base.

6. A switching apparatus, according to claim 5, wherein the center ofeach coiled portion is fixed to a movable shaft so that the shaftapproaches the base when the spring plate is bent,

and the coiled portions are forced to contact the base with the shaftsas their fulcrum when the spring plate is released.

7. A switching apparatus, according to claim 1, wherein at least oneroller made of magnetic material is mounted on at least one end of thebase which is formed to be straight so that the roller can roll towardthe center of the base and can be kept by resetting means at the end ofthe base in a normal condition whenever no pressure is applied to thespring plate, and at least one end of the spring plate is fixed to theouter surface of the roller so that the spring plate can be magneticallyconnected to the base through the roller and the intermediate portion ofthe spring plate can be bent with rotation of the roller.

8. A switching apparatus, according to claim 7, wherein at least onegalvano-magnetro effect device is provided at the free end side of themagnetic block so that the galvano-magnetro effect device contacts theroller when the spring plate is released.

9. A switching apparatus, according to claim 7, wherein a reluctanceincreasing part is provided in the axial direction of the roller on theouter surface of the roller mounted at the free end side of the magneticblock so that the reluctance increasing part contacts the base when theroller rotates with bending of the spring plate.

10. A switching apparatus, according to claim 7, wherein a reluctanceincreasing part is provided at the end of the magnetic block the rollercontacting said reluctance increasing part when the roller is rotatedwith bending of the spring plate.

1. A switching apparatus comprised of a. a base made of magneticmaterial which is composed of a magnet and a magnetic block coupled toand contacting a magnetic pole surface of the magnet, said base havingends; b. a spring plate made of magnetic material which is extendedbetween the ends of the base while being coupled magnetically to thebase and arranged so that it is positioned opposite to the base; c.means to bend the spring plate toward the base; d. a short-circuitingportion which is arranged between the spring plate and the base so thatit can approach the base to form a closed short-circuiting magnetic pathincluding the magnet when the spring plate is bent toward the base; ande. at least one galvano-magnetro effect device which is provided on thebase so that the density of the magnetic flux applied to the devicevaries when a closed short-circuiting magnetic path is formed with theshort-circuiting portion by bending of the spring plate.
 2. A switchingapparatus, according to claim 1, wherein at least one galvano-magnetroeffect device is provided at the magnetic block of the base so that theshort-circuiting portion can contact or approach the base when thespring plate is bent.
 3. A switching apparatus, according to claim 1,wherein yokes are provided at both ends of the base so that these yokesproject parallel to each other above the base and the ends of the springplate are slidably attached to the yokes.
 4. A switching apparatus,according to claim 1, wherein the ends of the spring plate are curved toform free ends opposite to each other and these free ends are fixed tothe ends of the base.
 5. A switching apparatus, according to claim 1,wherein at least one end of the spring plate is coiled and the portionsthus coiled are magnetically connected to the base.
 6. A switchingapparatus, according to claim 5, wherein the center of each coiledportion is fixed to a movable shaft so that the shaft approaches thebase when the spring plate is bent, and the coiled portions are forcedto contact the base with the shafts as their fulcrum when the springplate is released.
 7. A switching apparatus, according to claim 1,wherein at least one roller made of magnetic material is mounted on atleast one end of the base which is formed to be straight so that theroller can roll toward the center of the base and can be kept byresetting means at the end of the base in a normal condition whenever nopressure is applied to the spring plate, and at least one end of thespring plate is fixed to the outer surface of the roller so that thespring plate can be magnetically connected to the base through theroller and the intermediate portion of the spring plate can be bent withrotation of the roller.
 8. A switching apparatus, according to claim 7,wherein at least one galvano-magnetro effect device is provided at thefree end side of the magnetic block so that the galvano-magnetro Effectdevice contacts the roller when the spring plate is released.
 9. Aswitching apparatus, according to claim 7, wherein a reluctanceincreasing part is provided in the axial direction of the roller on theouter surface of the roller mounted at the free end side of the magneticblock so that the reluctance increasing part contacts the base when theroller rotates with bending of the spring plate.
 10. A switchingapparatus, according to claim 7, wherein a reluctance increasing part isprovided at the end of the magnetic block the roller contacting saidreluctance increasing part when the roller is rotated with bending ofthe spring plate.